The present invention relates to a bottle made of a saturated polyester resin provided with a vertically extending, strip-shaped projection on the trunk thereof.
The saturated polyester resins attract public attention for use as the materials for bottles, since they prevent soaking of any harmful materials such as solvent differing from other synthetic resinous materials conventionally used for making bottles and no poisonous gas is generated when combusted after disposal. However, melted saturated polyester resin is poorer or defficient in fluidity as compared to other meltable materials and tends to gelatinize to make it difficult to mold therefrom a bottle of complicated contour and to form an embossed pattern on the outer face of the bottle.
Further, the parison made of a saturated polyester resin in crystallized at the glass transition temperature due to the interrelation between the temperature and the time to lose its elongation capacity. As a result, it is necessary to maintain the temperature within an appropriate image if the parison made of a saturated polyeser resin is biaxially orientated and it is extremely difficult effect the desired biaxial orientation particularly when the thickness of the parison is varied in parts.